- To evaluate the persistence of antibodies and the presence of immune memory induced by a 3-dose primary vaccination with Tritanrix™-HepB/Hib-MenAC (three formulations) in the study DTPwHB/HibMenACTT001 (CPMS No. 759346/001) by giving unconjugated PRP, PSA and PSC at 10 months age to one subset of subjects.